computation of the combined solution of … of the combined solution of euref gps campaigns...

1

State Geodetic AdministrationGruška 20, HR-10 000 Zagreb

M. Marjanoviæ, Ž. Baèiæ

COMPUTATION OF THE COMBINED SOLUTION OFEUREF GPS CAMPAIGNS 1994-1996 IN THE

REPUBLIC OF CROATIA

The GPS Campaigns in the Republic of Croatia and the Republic of Slovenia carried out in1994, 1995 and 1996 were used to establish a connection to EUREF reference system and toestablish a reference GPS network in participating countries. The project was done with greatsupport of the German Institut für Angewandte Geodäsie (today Bundesamt für Kartographieund Geodäsie - BKG) in cooperation with State Geodetic Administration of the Republic ofCroatia, Surveying and Mapping Authority of the Republic of Slovenia and Faculty ofGeodesy, University of Zagreb. The great effort on the succesful finishing of the wholeproject was made by Hermann Seeger, the late Krešimir Èoliæ, Branimir Gojèeta, the lateDušan Miškoviæ, Yueksel Altiner, Tomislav Bašiæ, Božena Lipej, Zlatko Mediæ, Ljerka Rašiæand Aleš Seliškar.

1. Introduction

The EUREF 1994 Croatia and Slovenia GPS Campaign was carried out in order to connectCroatian and Slovenian networks to the EUREF-89 reference network. Fifteen new sites wereincluded in this campaign (10 in Croatia and 5 (+3) in Slovenia). The observations wereperformed from May 30 to June 3, 1994 (four days with a session length of 24 hours each). Inorder to establish reference GPS network in Slovenia, the SLOVENIA 1995 GPS Campaignwas carried out together with CROREF 1995 GPS Campaign in Croatia. The GPS networkconsists of 47 stations in Slovenia and 14 stations in Croatia. The observations wereperformed from September 25 to October 2, 1995, in two phases with 3 day observation each(session length of each observation day was 24 hours). The CROREF 1996 GPS Campaignwas the second EUREF campaign in Croatia and also GPS campaign to determine the firstand second order Croatian reference network. The GPS campaign was observed from August29 to September 12, 1996 (four phases, altogether nine sessions with session length of 24hours). In CROREF-96 campaign were also included all GPS sites observed withinCRODYN-96 GPS campaign (phase four).

After each observation campaign the data were processed using the Bernese GPS Softwarewith respect to the procedures specified by the EUREF Technical working group (Boucherand Altamimi, 1993). In view of different epochs of observation and therefore different orbitreference frames used in the data processing, the results of computed coordinates in theindividual GPS campaigns were expressed based on different ITRF realizations. The

2

processing of the SLOCRO-94 GPS Campaign (Lj. Rašiæ, M. Marjanoviæ) was computed inITRF-92, epoch 1994.4, the processing of SLOVENIA-95/CROREF-95 (D. Tavèar) wascomputed in ITRF-93, epoch 1995.7, and the processing of CROREF-96 and CRODYN-96(M. Marjanoviæ, Lj. Rašiæ) was computed in ITRF-94, epoch 1996.7. The differences betweenindividual solutions at identical observed sites displayed significant discrepancies aftertransformation to the ETRS-89. A possible reason for resulting differences could be the use ofdifferent reference systems. The ITRF reference system was improved with every realizationdue to improvement of measurement techniques, increasing number of included solutionsachieved by different observation methods and increasing number of included reference andpermanent sites.

Because of all these reasons, at one of TWG meetings the idea was born to re-compute eachcampaign in the ITRF-96 reference frame at observation epoch and then to compute onecombined solution in ITRF-96 reference frame at the middle epoch. Because of someproblems noted in combined solution and impossibility of using data of first originalcomputation due to different computer systems, we decided at State Geodetic Administrationto re-compute all three observed GPS campaigns and to compute a new combined solution.

2. GPS observation campaigns

The re-computed GPS campaigns SLOCRO-94, SLOVENIA-95/CROREF-95 and CROREF-96 were observed in three epochs. Complete set of data for the re-computation was used forGPS campaigns SLOCRO-94 and CROREF-96; for the SLOVENIA-95/CROREF-95 the dataof 9 GPS sites in Slovenia (of altogether 47) were used for control and better combination:

Site SLOCRO-94 SLOVENIA-95/CROREF-95

CROREF-96

IGS reference site 3 4 4IGS control site 2 5 7Austria 1 - -Bosnia and Herz. - - 5Croatia 10 14 76Slovenia 8 9 5

Ó 24 32 97

Altogether 105 GPS sites were included in the combined solution: 11 IGS sites, 1 site inAustria, 5 sites in Bosnia and Herzegowina, 78 sites in Croatia and 10 sites in Slovenia. Allnew GPS stations were occupied with TRIMBLE (SSE or SSI) GPS receivers usingcorresponding TRIMBLE GPS antennas (4000ST L1/L GEOD or TR GEOD L1/L2 GP). Formore information about GPS campaigns, observed sites and duration of the GPSmeasurements see Figure 1 and Table 1.

3. Coordinates of Reference IGS Sites

The coordinates of the reference IGS sites Graz, Matera, Zimmerwald and Wettzell-1202were used for the computation. The official set of coordinates in ITRF-96 reference frame isgiven for epoch 1997.0 together with the corresponding velocity field.

3

Sites observed 1994.



Sites observed 1994. and 1995.


LEGEND:


Sites observed 1994., 1995. and 1996.

4

NUM STATION NAME NUMBER 1994. 1995. 1996.OF 30.05.1994 - 3.06.1994. 25.09.1995 - 2.10.1995. 29.08.1996 -

12.09.1996.SESSIONS 150 151 152 153 268 269 270 271 272 273 274 242 243 245 246 249 250 253 254 255

1 BRUS 20 X X X X X X X X X X X X X X X X X X X X

2 KOSG 13 X X X X X X X X X X X X X3 BRUSNIK 0727 20 X X X X X X X X X X X X X X X X X X X X4 DONACKA GORA 7 X X X X X X X5 LEND GORICE 0720 16 X X X X X X X X X X X X X X X X6 VELIKA KOPA 7 X X X X X X X7 DONJI MIHOL 0725 6 X X X X X X8 GRADISTE 0728 8 X X X X X X X X9 NOVOS BRDO 0726 16 X X X X X X X X X X X X X X X X10 GRAZ 20 X X X X X X X X X X X X X X X X X X X X11 GOLICA 7 X X X X X X X12 KORADA 11 X X X X X X X X X X X13 REISSECK 4 X X X X14 ILIN VRH 0724 13 X X X X X X X X X X X X X15 SVETI IVAN 0733 7 X X X X X X X16 MALIJA 0724 20 X X X X X X X X X X X X X X X X X X X X17 KUCELJ 0722 20 X X X X X X X X X X X X X X X X X X X X18 SNEZNIK 11 X X X X X X X X X X X19 MATERA 20 X X X X X X X X X X X X X X X X X X X X20 PULA 0729 16 X X X X X X X X X X X X X X X X21 SATORINA 4 X X X X22 ZIRJE 0731 13 X X X X X X X X X X X X X23 HVAR 0732 7 X X X X X X X24 ZIMMERWALD 19 X X X X X X X X X X X X X X X X X X X25 KALNIK 222 9 X X X X X X X X X

TABLE 1: SLOCRO-1994, SLOVENIA-1995/CROREF-1995,CROREF-1996

5


12.09.1996.SESSIONS 150 151 152 153 268 269 270 271 272 273 274 242 243 245 246 249 250 253 254 255

26 PRIVIS 194 5 X X X X X

27 MONTAUR 182 5 X X X X X28 PADOVA 16 X X X X X X X X X X X X X X X X29 BLEGOS 5051 6 X X X X X X30 UCKA TRIG 183 EC 3 X X X31 BIJELA LASIC 193 5 X X X X X32 TUHOBIC 184 5 X X X X X33 GOPE 16 X X X X X X X X X X X X X X X X34 BOR1 15 X X X X X X X X X X X X X X X35 HFLK 16 X X X X X X X X X X X X X X X X36 WETTZELL-1202 16 X X X X X X X X X X X X X X X X37 SAMOB PLJES 196 5 X X X X X38 GORJANCI 375 5 X X X X X39 SLJEME 514 7 X X X X X X X40 KOTORIBA 389 5 X X X X X41 IVANCICA 209 5 X X X X X42 KALUD GROB 314 2 X X43 KLOSTAR IVAN 210 2 X X44 KOZJACA 522 2 X X45 KUDIC BRDO 235 2 X X46 VALPOVO 404 2 X X47 PENC 9 X X X X X X X X X48 GRADINA 401 2 X X49 VEL JAVORNIK 326 2 X X50 DAKOVO 363 2 X X51 SLAV BROD 258 2 X X

Continuation of TABLE 1

6


12.09.1996.SESSIONS 150 151 152 153 268 269 270 271 272 273 274 242 243 245 246 249 250 253 254 255

52 TURIC 394 2 X X

53 BREZIC 403 2 X X54 KAPOVAC 248 2 X X55 FERDINAN VIS 208 2 X X56 OSIJEK 249 2 X X57 MOLVE 316 2 X X58 BABJAK 527 2 X X59 GORICE 362 2 X X60 ALIJE 200 4 X X X X61 SARAJEVO 1447 4 X X X X62 PETROVAC 197 2 X X63 SISAK 20 2 X X64 ROVINJ 5001 2 X X65 SAVUDRIJA 8 2 X X66 PERUSIC 215 2 X X67 VELEB PLJES 190 2 X X68 PLITVICE 50 2 X X69 PRISEKA 198 2 X X70 VELI VRH 5007 2 X X71 BAKAR 5002 2 X X72 UCKA TRIG 183 2 X X73 IVSIC BRDO 101 3 X X X74 GRADAC PAG 235 2 X X75 OSOR 188 4 X X X X76 PILOSCAK 150 2 X X77 OSTRI 30 2 X X


7


12.09.1996.SESSIONS 150 151 152 153 268 269 270 271 272 273 274 242 243 245 246 249 250 253 254 255

78 VEL STRAZA 303 2 X X

79 PRAPATNICA 301 2 X X80 BERCASTAC 547 2 X X81 IST STRAZA 287 2 X X82 KARLOBAG 534 4 X X X X83 VRCEVO 291G 2 X X84 SIBENIK R13 2 X X85 SVILAJA 294 5 X X X X X86 VIS HUM 5008 5 X X X X X87 TREBACNIK 525 2 X X88 VEL VITRENIK 579 2 X X89 KREMEN 2 X X90 TIJARICA 5013 5 X X X X X91 CVRSNICA 280 2 X X92 VEL PROMINA 292 2 X X93 SVET ANDRIJA 316 2 X X94 MAKARSKA R96 3 X X X95 DUBROVNIK 5005 3 X X X96 ALADIN BRDO 282 3 X X X97 ZUTA LOKVA 5011 3 X X X98 ZADAR 5003 3 X X X99 UCKA 5006 3 X X X100 KOPER 5052 3 X X X101 KAPELA 5012 3 X X X102 SPLIT 5004 3 X X X103 MOSOR 300 3 X X X104 LASTOVO 5009 3 X X X105 PALAGRUZA 5010 3 X X X


8

The following table contains the coordinates of reference sites in ITRF-96, 1997.0, with theirvelocities and transformed coordinates in ITRF-96, epochs 1994.4, 1995.5, 1996.7 and1995.55.

Site name ITRF96 ITRF96 ITRF96 ITRF96 ITRF96 ITRF96Epoch 1997.0 Epoch 1997.0 Epoch 1994.4 Epoch 1995.7 Epoch 1996.7 Epoch 1995.55

X,Y,Z Vx,Vy,Vz X,Y,Z X,Y,Z X,Y,Z X,Y,Z

Graz 4194423.968 -0.0154 4194424.0080 4194423.9880 4194423.9726 4194423.99031162702.559 0.0187 1162702.5104 1162702.5347 1162702.5534 1162702.53194647245.314 0.0104 4647245.2870 4647245.3005 4647245.3109 4647245.2989

Matera 4641949.718 -0.0189 4641949.7671 4641949.7426 4641949.7237 4641949.74541393045.282 0.0192 1393045.2321 1393045.2570 1393045.2762 1393045.25424133287.333 0.0136 4133287.2976 4133287.3153 4133287.3289 4133287.3133

Zimmerwald 4331297.201 -0.0111 4331297.2299 4331297.2154 4331297.2043 4331297.2171567555.740 0.0173 567555.6950 567555.7175 567555.7348 567555.7149

4633133.843 0.0126 4633133.8102 4633133.8266 4633133.8392 4633133.8247Wettzell 4075580.697 -0.0159 4075580.7177 4075580.7018 4075580.7201

931853.669 0.0174 931853.6464 931853.6638 931853.64384801568.044 0.0070 4801568.0349 4801568.0419 4801568.0339

In the new re-computation were also included permanent IGS sites which were handled andprocessed as any other new GPS site in order to provide control of computed coordinates inindividual campaign solutions and combined solution.

The following table contains the coordinates of permanent IGS sites in ITRF-96, 1997.0, withtheir velocities and transformed coordinates in ITRF-96, epochs 1994.4, 1995.5, 1996.7 and1995.55.

Site name ITRF96 ITRF96 ITRF96 ITRF96 ITRF96 ITRF96Epoch 1997.0 Epoch 1997.0 Epoch 1994.4 Epoch 1995.7 Epoch 1996.7 Epoch 1995.55

X,Y,Z Vx,Vy,Vz X,Y,Z X,Y,Z X,Y,Z X,Y,Z

Kootwijk 3899225.259 -0.0132 3899225.2933 3899225.2630 3899225.2781396731.819 0.0163 396731.7766 396731.8141 396731.7954

5015078.345 0.0100 5015078.3190 5015078.3420 5015078.3305Borowiec 3738358.611 -0.0158 3738358.6315 3738358.6157 3738358.6339

1148173.592 0.0153 1148173.5721 1148173.5874 1148173.56985021815.697 0.0083 5021815.6862 5021815.6945 5021815.6850

Brussels 4027893.866 -0.0103 4027893.8928 4027893.8794 4027893.8691 4027893.8809307045.699 0.0176 307045.6532 307045.6761 307045.6937 307045.6735

4919475.031 0.0120 4919474.9998 4919475.0154 4919475.0274 4919475.0136Hafelekar 4248505.189 -0.0147 4248505.2081 4248505.1934 4248505.2103

855575.605 0.0207 855575.5781 855575.5988 855575.57504667172.186 0.0117 4667172.1708 4667172.1825 4667172.1690

Pecny 3979316.275 -0.0138 3979316.2929 3979316.2791 3979316.29501050312.351 0.0182 1050312.3273 1050312.3455 1050312.32464857067.013 0.0092 4857067.0010 4857067.0102 4857066.9997

Penc 4052449.640 -0.0152 4052449.6446 4052449.66201417680.998 0.0184 1417680.9925 1417680.97134701407.027 0.0090 4701407.0243 4701407.0140

Padova 4389531.299 -0.0140 4389531.3172 4389531.3032 4389531.3193923253.651 0.0166 923253.6294 923253.6460 923253.6269

4519256.340 0.0121 4519256.3243 4519256.3364 4519256.3225

9

4. Processing Strategy

The data were processed using the post-processing Bernese GPS Software Version 4.0 withrespect to the procedures specifed by EUREF Technical working group.

The following principles were applied in the data processing:

− use of final IGS precise orbits with corresponding earth rotation parameters,− for the pre-processing and processing 24 hours of 15-second-interval data were used,− minimun elevation angle of 15 degrees was used for the 1994. and 1995. campaigns, and

20 degrees for the 1996. campaign,− application of antenna elevation-dependent phase center corrections, because different

types of antennas were combined,− the standard troposphere model of Saastamoinen was applied (one site troposphere

parameter on each 2 hours; a-priori sigma for absolute and relative troposphere parametersis ± 9.999 m),

− processing of the double-difference measurements based on the ionosphere-free carrierphase linear combination L3,

− ionosphere model was used for the resolving of L5 ambiguities,− ambiguity resolution L1 and L2 (sigma resolution for baselines up to 100 km and QIF

resolution for longer baselines), approximately 90% of ambiguities were solved,− correlations modelled correctly,− free solution of each session (normal equations, estimated station coordinates and

troposphere parameters were saved),− the normal equations from each processing session were combined using ADDNEQ

program to create a free campaign solution,− the normal equations from each processing session were combined using ADDNEQ

program to create a constrained campaign solution in order to compare the coordinates ofcontrol IGS sites with computed values.

In order to compute the combined solution, all three GPS campaigns have to be processed inthe same reference frame, therefore precise IGS orbits from its original ITRF reference frame(ITRF-92, ITRF-93, ITRF-94) were transformed into the ITRF-96 reference frame using theprogram TRNFSP3N of J. Kouba with associated transformation parameters. The sameprogram was also used for the transformation of corresponding IGS earth rotation parameters.

The computations of individual GPS campagins was done using orbits in its original referenceframe (ITRF-92, ITRF-93 and ITRF-94) and transformed orbits in ITRF-96 with fixing ofreference IGS sites in ITRF-96 in order to investigate influence of orbit transformation tocomputed coordinates and to control transformation procedure. The differences of solutions ofeach GPS campaign for X, Y, and Z component in millimeters are presented in the followingdiagrams:

10

SLOCRO-1994 GPS Campaign:

CROREF-1995 GPS Campaign:

-3

-2

-1

0

1

2

3IL

IN V

RH

0724

BR

US

NIK

0727

NO

VO

S B

RD

O 0

726

ZIR

JE 0

731

PU

LA

0729

LE

ND

GO

RIC

E 0

720

MA

LIJ

A 0

724

KU

CE

LJ

0722

GR

AD

IST

E 0

728

DO

NJI

MIH

OL 0

725

HV

AR

0732

SV

ET

I IV

AN

0733

BR

US

KO

SG

VE

LIK

A K

OP

A

KO

RA

DA

SN

EZ

NIK

DO

NA

CK

A G

OR

A

GO

LIC

A

RE

ISS

EC

K

SA

TO

RIN

A

X

Y

Z

-3

-2

-1

0

1

2

3

PA

DO

VA

BR

US

NIK

0727

NO

VO

S B

RD

O 0

726

PU

LA

0729

LE

ND

GO

RIC

E 0

720

MA

LIJ

A 0

724

KU

CE

LJ

0722

SA

MO

B P

LJE

S 1

96

SLJE

ME

514

KO

TO

RIB

A 3

89

KA

LN

IK 2

22

PR

IVIS

194

GO

RJA

NC

I 375

MO

NT

AU

R 1

82

IVA

NC

ICA

209

BIJ

ELA

LA

SIC

193

BLE

GO

S 5

051

BO

R1

BR

US

GO

PE

HF

LK

TU

HO

BIC

184

VE

LIK

A K

OP

A

KO

RA

DA

SN

EZ

NIK

DO

NA

CK

A G

OR

A

GO

LIC

A

UC

KA

TR

IG 1

83

X

Y

Z

11

CROREF-1996 GPS Campaign:

5. Individual Campaign Solutions

The re-computation started with the processing of each individual GPS campaign to getinformation about the quality and accuracy of each campaign and to produce all necessarydata needed for the computation of the combined solution. The information about antennatypes and antenna heights was once again independently controlled for all observed GPS siteswithin each of individual GPS campaigns.

The computations were carried out on the basis of the ITRF-96 reference frame. Due to theuse of differenced phase observations in the Bernese GPS Software, single differences ofphase data were formed between stations for each session following the principles of baselineminimum length and using identical baselines for all days of one campaign if possible. In thepre-processing and processing steps complete set of data was used without decreasing thesampling rate used during the observation time. The cycle slips were fixed, bad data were

-3

-2

-1

0

1

2

3P

AD

OV

A

PE

NC

ILIN

VR

H 0

724

BR

US

NIK

0727

NO

VO

S B

RD

O 0

726

ZIR

JE 0

731

PU

LA

0729

LE

ND

GO

RIC

E 0

720

MA

LIJ

A 0

724

KU

CE

LJ

0722

KLO

ST

AR

IV

AN

210

KO

ZJA

CA

522

SA

MO

B P

LJE

S 1

96

SLJE

ME

514

GR

AD

IST

E 0

728

DO

NJI

MIH

OL 0

725

VE

LI

VR

H 5

007

IST

ST

RA

ZA

287

SV

ET

AN

DR

IJA

316

VA

LP

OV

O 4

04

SIS

AK

20

GR

AD

INA

401

PE

RU

SIC

215

PR

AP

AT

NIC

A 3

01

ZA

DA

R 5

003

VIS

HU

M 5

008

VE

L J

AV

OR

NIK

326

PR

ISE

KA

198

VE

L S

TR

AZ

A 3

03

PA

LA

GR

UZ

A 5

010

SA

VU

DR

IJA

8

VE

LE

B P

LJE

S 1

90

TR

EB

AC

NIK

525

KA

RLO

BA

G 5

34

UC

KA

TR

IG 1

83

BA

KA

R 5

002

KO

TO

RIB

A 3

89

OS

OR

188

KA

PE

LA

5012

KA

LN

IK 2

22

PR

IVIS

194

DA

KO

VO

363

PLIT

VIC

E 5

0

SIB

EN

IK R

13

HV

AR

0732

BR

EZ

IC 4

03

IVS

IC B

RD

O 1

01

X

Y

Z

-3

-2

-1

0

1

2

3

MA

KA

RS

KA

R96

KA

PO

VA

C 2

48

PE

TR

OV

AC

197

BE

RC

AS

TA

C 5

47

ZU

TA

LO

KV

A 5

011

FE

RD

INA

N V

IS 2

08

GR

AD

AC

PA

G 2

35

SV

ILA

JA 2

94

OS

IJE

K 2

49

GO

RJA

NC

I 375

VR

CE

VO

291G

DU

BR

OV

NIK

5005

UC

KA

5006

SP

LIT

5004

MO

LV

E 3

16

RO

VIN

J 5001

LA

ST

OV

O 5

009

TIJ

AR

ICA

5013

BA

BJA

K 5

27

PIL

OS

CA

K 1

50

SLA

V B

RO

D 2

58

MO

NT

AU

R 1

82

IVA

NC

ICA

209

BIJ

ELA

LA

SIC

193

VE

L V

ITR

EN

IK 5

79

SV

ET

I IV

AN

0733

GO

RIC

E 3

62

OS

TR

I 30

ALA

DIN

BR

DO

282

KU

DIC

BR

DO

235

BLE

GO

S 5

051

KO

PE

R 5

052

KR

EM

EN

SA

RA

JEV

O 1

447

TU

RIC

394

CV

RS

NIC

A 2

80

BO

R1

BR

US

GO

PE

HF

LK

KO

SG

ALIJ

E 2

00

VE

L P

RO

MIN

A 2

92

MO

SO

R 3

00

KA

LU

D G

RO

B 3

14

TU

HO

BIC

184

X

Y

Z

12

marked and new ambiguities were set up. In the first processing step the initial phaseambiguities were solved for each baseline using SIGMA strategy for baselines up to 100 km(at first L5 linear combination + ionosphere model, than L3 linear combination) and QIFstrategy for longer baselines, approximately 90% of ambiguities were solved. In the secondstep the daily solutions were computed in which the fixed ambiguities were used, thecoordinates of reference sites were estimated with a-priori constraints of ± 0.0005 m and 12troposphere parameters per station and session were estimated.

In order to get information about the quality of the data and to analyse comparisons with theofficial reference coordinates of control sites in ITRF-96 for each campaign, one constrainedsolution (included all sessions of individual campaign) was computed.

In the next paragraphs the following results are presented for the each of individual GPScampaigns:a) comparison of station coordinates with respect to the combined campaign solution (RMS

of individual coordinate residuals) in millimeters,b) RMS values with respect to the combined solution (daily solutions – combined campaign

solution) in millimeters.c) comparison of computed IGS control sites with official ITRF-96 values.

5.1 SLOCRO-1994 GPS Campaign

In the SLOCRO-1994 GPS campaign a total of 24 GPS sites (3 reference IGS sites + 2control IGS sites + 21 new GPS sites) was included. The complete network contains 92baselines divided in four sessions.

a)

0

5

10

15

20

BR

US

KO

SG

BR

US

NIK

0727

DO

NA

CK

A G

OR

A

LE

ND

GO

RIC

E 0

720

VE

LIK

A K

OP

A

DO

NJI

MIH

OL 0

725

GR

AD

IST

E 0

728

NO

VO

S B

RD

O 0

726

GO

LIC

A

KO

RA

DA

RE

ISS

EC

K

ILIN

VR

H 0

724

SV

ET

I IV

AN

0733

MA

LIJ

A 0

724

KU

CE

LJ

0722

SN

EZ

NIK

PU

LA

0729

SA

TO

RIN

A

ZIR

JE 0

731

HV

AR

0732

North East Up

13

b)Param. RMS 150 151 152 153

North 1.2 1.4 1.2 1.3 1.1

East 1.3 1.6 1.4 0.9 1.1Up 5.3 5.6 5.5 3.8 6.2

Stations 24 24 24 24 24

c)

Num Station name Parameter ITRF Coordinates Computed coordinates DifferenceITRF96, Epoch 1994.4 ITRF96, Epoch 1994.4 (m)

88 BRUS X 4027893.893 4027893.902 0.009Y 307045.653 307045.653 0.000Z 4919475.000 4919475.003 0.003

HEIGHT 149.667 149.675 0.008LATITUDE 50 47 52.139134 50 47 52.138956 -0.006

LONGITUDE 4 21 33.179766 4 21 33.179742 -0.001

91 KOSG X 3899225.293 3899225.298 0.005Y 396731.777 396731.775 -0.002Z 5015078.319 5015078.319 0.000

HEIGHT 96.855 96.857 0.003LATITUDE 52 10 42.330379 52 10 42.330269 -0.003

LONGITUDE 5 48 34.708758 5 48 34.708642 -0.002

5.2 SLOVENIA-1995/CROREF-1995

In the SLOVENIA-1995/CROREF-1995 GPS campaign a total of 32 GPS sites (4 referenceIGS sites + 5 control IGS sites + 23 new GPS sites) was included. The complete networkcontains 149 baselines divided in seven sessions.

a)

0

5

10

15

20

BR

US

NIK

0727

KA

LN

IK 2

22

PR

IVIS

194

MA

LIJ

A 0

724

MO

NT

AU

R 1

82

PA

DO

VA

KU

CE

LJ

0722

BLE

GO

S 5

051

SN

EZ

NIK

PU

LA

0729

UC

KA

TR

IG 1

83 E

C

BIJ

ELA

LA

SIC

193

TU

HO

BIC

184

GO

LIC

A

KO

RA

DA

GO

PE

BO

R1

HF

LK

BR

US

NO

VO

S B

RD

O 0

726

SA

MO

B P

LJE

S 1

96

GO

RJA

NC

I 375

VE

LIK

A K

OP

A

SLJE

ME

514

KO

TO

RIB

A 3

89

LE

ND

GO

RIC

E 0

720

IVA

NC

ICA

209

DO

NA

CK

A G

OR

A

North East Up

14

b)

Param. RMS 268 269 270 271 272 273 274

North 1.3 1.2 1.5 1.8 0.9 1.2 0.9 1.5East 1.5 1.5 1.0 2.7 0.7 0.9 1.1 1.5Up 4.0 3.7 5.0 4.8 4.5 3.9 3.0 3.8

Stations 32 23 23 23 15 24 24 24

c)


3 PADOVA X 4389531.317 4389531.318 0.001Y 923253.629 923253.629 -0.001Z 4519256.324 4519256.322 -0.002

HEIGHT 84.042 84.041 -0.001LATITUDE 45 24 24.180613 45 24 24.180546 -0.002

LONGITUDE 11 52 40.550741 11 52 40.550693 -0.001

89 GOPE X 3979316.293 3979316.296 0.003Y 1050312.327 1050312.336 0.009Z 4857067.001 4857067.006 0.005

HEIGHT 592.598 592.605 0.007LATITUDE 49 54 49.331703 49 54 49.331662 -0.001

LONGITUDE 14 47 8.231090 14 47 8.231485 0.008

87 BOR1 X 3738358.632 3738358.627 -0.005Y 1148173.572 1148173.576 0.004Z 5021815.686 5021815.681 -0.005

HEIGHT 124.374 124.368 -0.006LATITUDE 52 16 37.039403 52 16 37.039385 -0.001

LONGITUDE 17 4 24.433430 17 4 24.433697 0.005

90 HFLK X 4248505.208 4248505.213 0.005Y 855575.578 855575.583 0.005Z 4667172.171 4667172.171 0.000

HEIGHT 2384.141 2384.145 0.004LATITUDE 47 18 46.452315 47 18 46.452179 -0.004

LONGITUDE 11 23 9.922859 11 23 9.923052 0.004

88 BRUS X 4027893.879 4027893.879 0.000Y 307045.676 307045.678 0.002Z 4919475.015 4919475.016 0.001

HEIGHT 149.672 149.673 0.001LATITUDE 50 47 52.139745 50 47 52.139762 0.001

LONGITUDE 4 21 33.180984 4 21 33.181088 0.002

5.3 CROREF-1996 GPS Campaign

In the CROREF-1996 GPS campaign a total of 97 GPS sites (4 reference IGS sites + 7 controlIGS sites + 86 new GPS sites) was included. The complete network contains 353 baselinesdivided in nine sessions.

15

a)

b)Param. RMS 242 243 245 246 249 250 253 254 255

North 1.6 1.9 1.5 1.1 1.2 1.3 1.8 1.4 1.6 2.3East 2.0 1.9 3.4 2.3 2.1 1.9 1.3 1.2 1.5 1.5Up 5.4 5.8 5.5 5.9 5.2 7.6 5.8 3.8 4.0 4.8

Stations 97 45 45 44 43 36 35 37 39 38

0

5

10

15

20IL

IN V

RH

07

24

BR

US

NIK

07

27

SA

MO

B P

LJE

S 1

96

NO

VO

S B

RD

O 0

726

KA

LU

D G

RO

B 3

14

ZIR

JE

07

31

MA

LIJ

A 0

72

4

PU

LA

07

29

PA

DO

VA

KU

CE

LJ 0

72

2

KL

OS

TA

R I

VA

N 2

10

KO

ZJA

CA

52

2

KU

DIC

BR

DO

23

5

DO

NJI

MIH

OL 0

725

VA

LP

OV

O 4

04

PE

NC

GR

AD

INA

40

1

VE

L J

AV

OR

NIK

32

6

KO

TO

RIB

A 3

89

LE

ND

GO

RIC

E 0

72

0

KA

LN

IK 2

22

DA

KO

VO

36

3

GR

AD

IST

E 0

72

8

SL

AV

BR

OD

25

8

TU

RIC

39

4

BR

EZ

IC 4

03

KA

PO

VA

C 2

48

FE

RD

INA

N V

IS 2

08

OS

IJE

K 2

49

MO

LV

E 3

16

BA

BJA

K 5

27

GO

RIC

E 3

62

IVA

NC

ICA

20

9

SL

JE

ME

51

4

AL

IJE

20

0

BO

R1

GO

PE

BR

US

KO

SG

HF

LK

SA

RA

JE

VO

14

47

PR

IVIS

19

4

PE

TR

OV

AC

19

7

GO

RJA

NC

I 3

75

SIS

AK

20

RO

VIN

J 5

00

1

SA

VU

DR

IJA

8

North East Up

0

5

10

15

20

MO

NT

AU

R 1

82

PE

RU

SIC

21

5

VE

LE

B P

LJE

S 1

90

PL

ITV

ICE

50

PR

ISE

KA

19

8

VE

LI

VR

H 5

00

7

BA

KA

R 5

00

2

UC

KA

TR

IG 1

83

BIJ

EL

A L

AS

IC 1

93

TU

HO

BIC

18

4

IVS

IC B

RD

O 1

01

GR

AD

AC

PA

G 2

35

OS

OR

188

PIL

OS

CA

K 1

50

OS

TR

I 3

0

VE

L S

TR

AZ

A 3

03

PR

AP

AT

NIC

A 3

01

BE

RC

AS

TA

C 5

47

IST

ST

RA

ZA

28

7

KA

RL

OB

AG

53

4

VR

CE

VO

29

1G

SIB

EN

IK R

13

SV

ILA

JA

29

4

VIS

HU

M 5

00

8

TR

EB

AC

NIK

52

5

VE

L V

ITR

EN

IK 5

79

KR

EM

EN

TIJ

AR

ICA

50

13

CV

RS

NIC

A 2

80

VE

L P

RO

MIN

A 2

92

SV

ET

AN

DR

IJA

31

6

MA

KA

RS

KA

R9

6

DU

BR

OV

NIK

50

05

AL

AD

IN B

RD

O 2

82

ZU

TA

LO

KV

A 5

01

1

ZA

DA

R 5

00

3

UC

KA

50

06

KO

PE

R 5

05

2

BL

EG

OS

50

51

KA

PE

LA

50

12

HV

AR

07

32

SP

LIT

50

04

MO

SO

R 3

00

LA

ST

OV

O 5

00

9

PA

LA

GR

UZ

A 5

01

0

SV

ET

I IV

AN

07

33

North East Up

16

c)


3 PADOVA X 4389531.303 4389531.305 0.002Y 923253.646 923253.649 0.003Z 4519256.336 4519256.337 0.001

HEIGHT 84.043 84.045 0.002LATITUDE 45 24 24.181126 45 24 24.181084 -0.001

LONGITUDE 11 52 40.551621 11 52 40.551726 0.002

4 PENC X 4052449.645 4052449.642 -0.003Y 1417680.993 1417680.992 -0.001Z 4701407.024 4701407.023 -0.002

HEIGHT 291.749 291.746 -0.003LATITUDE 47 47 22.566566 47 47 22.566605 0.001

LONGITUDE 19 16 53.494784 19 16 53.494803 0.000

87 BOR1 X 3738358.616 3738358.609 -0.007Y 1148173.587 1148173.585 -0.002Z 5021815.695 5021815.685 -0.009

HEIGHT 124.374 124.362 -0.012LATITUDE 52 16 37.039839 52 16 37.039845 0.000

LONGITUDE 17 4 24.434446 17 4 24.434442 0.000

89 GOPE X 3979316.279 3979316.271 -0.008Y 1050312.346 1050312.345 -0.001Z 4857067.010 4857066.999 -0.011

HEIGHT 592.599 592.585 -0.014LATITUDE 49 54 49.332110 49 54 49.332081 -0.001

LONGITUDE 14 47 8.232148 14 47 8.232220 0.001

88 BRUS X 4027893.869 4027893.865 -0.005Y 307045.694 307045.694 0.000Z 4919475.025 4919475.021 -0.004

HEIGHT 149.674 149.668 -0.006LATITUDE 50 47 52.140159 50 47 52.140199 0.001

LONGITUDE 4 21 33.181920 4 21 33.181932 0.000

91 KOSG X 3899225.263 3899225.254 -0.009Y 396731.814 396731.812 -0.002Z 5015078.342 5015078.329 -0.013

HEIGHT 96.857 96.841 -0.016LATITUDE 52 10 42.331509 52 10 42.331497 0.000

LONGITUDE 5 48 34.710883 5 48 34.710817 -0.001

90 HFLK X 4248505.193 4248505.190 -0.004Y 855575.599 855575.599 0.000Z 4667172.183 4667172.177 -0.005

HEIGHT 2384.143 2384.137 -0.006LATITUDE 47 18 46.452817 47 18 46.452780 -0.001

LONGITUDE 11 23 9.923963 11 23 9.924004 0.001

17

6. Combined Solution

After the re-computation of individual GPS campaigns and analysis of computed results, thesecond group of information needed for the computation of combined solution was prepared.At first, the dimension of arrays in ADDNEQ program and its subroutines were adjusted dueto the large number of parameters and unknows. The free adjustment of three GPS campaignswas performed in three epochs (1994.4, 1995.7 and 1996.7) and as a result the normalequation files were saved.

In order to compute combined solution of all three GPS campaigns at the middle epoch,beside normal equation files also station velocities have to be given as input values. Thevelocities of four reference IGS sites (Graz, Matera, Zimmerwald and Wettzell) are ITRF-96velocities. The velocities of all other GPS sites were computed with the Bernese GPSSoftware program NUVELO on the basis of NUVEL1A-NNR model and station coordinatesin the EURA plate.

The estimated coordinates of the combined solution of all GPS campaigns refer to the ITRF-96 reference frame, at middle epoch 22.07.1995. which corresponds to epoch 1995.55.

RMS values with respect to the combined solution (individual campaign solutions –combined solution) in millimeters are:

Param. RMS SLOCRO-94 CROREF-95 CROREF-96

North 5.1 9.3 1.3 4.5East 3.0 2.2 3.6 3.0Up 6.3 7.9 3.4 6.7

Stations 105 24 32 97

Again, the coordinates of control IGS sites computed in combined solution with officialITRF-96 (epoch 1995.55) coordinates were compared. The differences between the two setsof coordinates are presented in the following table:

Num Station name Parameter ITRF Coordinates Combined Solution DifferenceITRF96, Epoch 1995.55 ITRF96, Epoch 1995.55 (m)

3 PADOVA X 4389531.319 4389531.321 -0.002Y 923253.627 923253.626 0.001Z 4519256.323 4519256.322 0.001

HEIGHT 84.042 84.042 0.000LATITUDE 45 24 24.180537 45 24 24.180492 0.001

LONGITUDE 11 52 40.550609 11 52 40.550569 0.001

4 PENC X 4052449.662 4052449.659 0.003Y 1417680.971 1417680.973 -0.001Z 4701407.014 4701407.010 0.004

HEIGHT 291.748 291.743 0.005LATITUDE 47 47 22.566116 47 47 22.566073 0.001

LONGITUDE 19 16 53.493546 19 16 53.493651 -0.002

18

Num Station name Parameter ITRF Coordinates Combined Solution DifferenceITRF96, Epoch 1995.55 ITRF96, Epoch 1995.55 (m)

87 BOR1 X 3738358.634 3738358.629 0.005Y 1148173.570 1148173.570 -0.001Z 5021815.685 5021815.678 0.007

HEIGHT 124.374 124.366 0.008LATITUDE 52 16 37.039338 52 16 37.039321 0.001

LONGITUDE 17 04 24.433277 17 4 24.433378 -0.002

89 GOPE X 3979316.295 3979316.295 0.000Y 1050312.325 1050312.330 -0.005Z 4857067.000 4857066.998 0.001

HEIGHT 592.598 592.598 0.000LATITUDE 49 54 49.331642 49 54 49.331573 0.002

LONGITUDE 14 47 08.230932 14 47 8.231192 -0.005

88 BRUS X 4027893.881 4027893.882 -0.001Y 307045.674 307045.674 0.000Z 4919475.014 4919475.014 0.000

HEIGHT 149.671 149.672 -0.001LATITUDE 50 47 52.139675 50 47 52.139651 0.001

LONGITUDE 4 21 33.180846 4 21 33.180861 0.001

91 KOSG X 3899225.278 3899225.274 0.004Y 396731.795 396731.793 0.002Z 5015078.331 5015078.325 0.005

HEIGHT 96.855 96.849 0.006LATITUDE 52 10 42.330945 52 10 42.330938 0.000

LONGITUDE 5 48 34.709824 5 48 34.709719 0.002

90 HFLK X 4248505.210 4248505.212 -0.002Y 855575.575 855575.579 -0.004Z 4667172.169 4667172.168 0.001

HEIGHT 2384.141 2384.142 -0.001LATITUDE 47 18 46.452239 47 18 46.452157 0.003

LONGITUDE 11 23 09.922694 11 23 9.922874 -0.004

7. Transformation into ETRS-89

The transformation into the ETRS-89 reference system was done following Specifications forreference frame fixing in the analysis of a EUREF GPS campaign (C.Boucher, Z. Altamimi,1998.):

)0.1989t()yy(t

0yyyy

yy0yy

yyyy0

yy)t(yy)t(e cc

12

13

23

cc −⋅⋅−

−−

++= XTXX

RR

RR

RR

,

where

)t(e cX - coordinates in ETRS-89,

)t(yy cX - coordinates in ITRF-96,

19

yyT - translation parameters (ITRF-96 to ETRS-89),

yyiR - rotation parameters (ITRF-96 to ETRS-89),

ct - observation epoch – 1995.55.

Transformation parameters:

T1 (cm) 4.1

T2 (cm) 4.1

T3 (cm) -4.9

1R (0.001 sec) 0.20

2R (0.001 sec) 0.50

3R (0.001 sec) -0.65

In order to provide control of combined solution, the coordinates of all individual constrainedGPS campaign solutions were transformed from their epoch of observation to ETRS-89 asdescribed:

GPS Campaign Reference Frame Epoch

SLOCRO-94 ITRF-96 1994.4

CROREF-95 ITRF-96 1995.7

CROREF-96 ITRF-96 1996.7

COMBINED SOLUTION ITRF-96 1995.55

The differences between each of individual GPS campaign solution after transformation toETRS-89 system and combined solution in ETRS-89 for all GPS sites are given in thefollowing tabel in millimeters:

GPS Campaign 94 - COM 95 - COM 96 - COM GPS Campaign 94 - COM 95 - COM 96 - COMGPS Site dX dY dZ dX dY dZ dX dY dZ GPS Site dX dY dZ dX dY dZ dX dY dZPADOVA -1 0 -1 0 1 4 ZUTA LOKVA 5011 1 0 4PENC 1 -1 3 FERDINAN VIS 208 -1 3 3

ILIN VRH 0724 1 -3 -8 1 1 5 GRADAC PAG 235 0 -3 1BRUSNIK 0727 -10 -1 -16 1 -1 1 2 2 5 SVILAJA 294 1 -1 4NOVOS BRDO 0726 -7 -1 -12 1 -4 2 3 3 4 OSIJEK 249 0 4 3

ZIRJE 0731 2 -4 -7 0 1 3 GORJANCI 375 -1 1 -2 0 3 4PULA 0729 2 1 -5 0 -1 -4 1 1 5 VRCEVO 291G 0 -1 4LEND GORICE 0720 20 12 -10 -9 16 -10 -4 -16 10 DUBROVNIK 5005 1 1 5

MALIJA 0724 13 2 3 -5 2 -2 1 -2 -1 UCKA 5006 1 -1 4KUCELJ 0722 -2 0 -10 -1 0 -2 2 2 7 SPLIT 5004 1 -1 4KLOSTAR IVAN 210 -1 3 2 MOLVE 316 1 3 3

20

GPS Campaign 94 - COM 95 - COM 96 - COM GPS Campaign 94 - COM 95 - COM 96 - COM

GPS Site dX dY dZ dX dY dZ dX dY dZ GPS Site dX dY dZ dX dY dZ dX dY dZKOZJACA 522 -1 3 2 ROVINJ 5001 0 0 2

SAMOB PLJES 196 0 0 0 -5 6 -3 LASTOVO 5009 1 1 5SLJEME 514 -2 0 -3 -2 6 4 TIJARICA 5013 1 -1 4GRADISTE 0728 1 -3 -9 2 7 7 BABJAK 527 0 3 3

DONJI MIHOL 0725 4 1 -2 -4 3 -6 PILOSCAK 150 0 0 2VELI VRH 5007 0 -3 2 SLAV BROD 258 0 3 3IST STRAZA 287 0 -1 3 MONTAUR 182 0 0 -1 -4 2 1

SVET ANDRIJA 316 1 1 5 IVANCICA 209 0 0 -1 -4 5 0VALPOVO 404 0 4 3 BIJELA LASIC 193 -3 1 -2 6 -3 7SISAK 20 1 2 4 VEL VITRENIK 579 1 -1 4

GRADINA 401 1 3 3 SVETI IVAN 0733 2 -2 -8 1 4 8PERUSIC 215 0 -2 1 GORICE 362 0 3 3PRAPATNICA 301 0 -1 4 OSTRI 30 0 0 2

ZADAR 5003 1 -1 4 ALADIN BRDO 282 1 1 5VIS HUM 5008 1 -1 4 KUDIC BRDO 235 -1 3 2VEL JAVORNIK 326 0 3 3 BLEGOS 5051 -5 2 -4 8 -2 10

PRISEKA 198 1 2 4 KOPER 5052 1 -1 4VEL STRAZA 303 1 -1 4 KREMEN 1 -1 4PALAGRUZA 5010 0 2 5 SARAJEVO 1447 0 2 3

SAVUDRIJA 8 0 0 2 TURIC 394 0 4 3VELEB PLJES 190 0 -3 2 CVRSNICA 280 1 -1 4TREBACNIK 525 1 -1 4 BOR1 0 3 2 -2 -4 -2

KARLOBAG 534 1 -1 4 BRUS 5 0 0 -1 2 1 -2 0 -4UCKA TRIG 183 0 0 2 GOPE 3 4 6 -7 -5 -9BAKAR 5002 0 -3 1 HFLK 3 1 1 -6 -1 -2

KOTORIBA 389 -2 -1 -2 2 7 4 KOSG 8 2 4 -5 -1 -6OSOR 188 0 -2 2 ALIJE 200 0 2 3KAPELA 5012 1 -1 5 VEL PROMINA 292 1 -1 4

KALNIK 222 -2 0 -2 8 9 11 MOSOR 300 1 1 5PRIVIS 194 3 0 3 -8 3 -4 KALUD GROB 314 0 3 3DAKOVO 363 0 4 3 TUHOBIC 184 -4 4 2 1 -10 -8

PLITVICE 50 0 -2 1 VELIKA KOPA 5 2 -1 -2 1 -5SIBENIK R13 1 -1 4 KORADA -4 1 -10 1 1 0HVAR 0732 3 0 -9 -1 1 9 SNEZNIK 2 2 -4 -1 1 -2

BREZIC 403 0 4 3 DONACKA GORA 4 2 -3 -2 1 -4IVSIC BRDO 101 0 -2 3 GOLICA 7 0 -2 -5 2 -4MAKARSKA R96 0 1 5 REISSECK 3 1 -5

KAPOVAC 248 0 3 3 SATORINA 2 0 -6PETROVAC 197 0 2 3 UCKA TRIG 183 EC -1 1 -1

BERCASTAC 547 1 -1 4

The above presented differences show good consistence of individual solutions in relation tothe combined solution. Specially the differences of GPS sites observed in only one campaignhave order of magnitude of few millimeters to combined solution. Those differences wereprobably caused by different weighting through adjustment process of combined solution ofall three GPS campaigns.

The EUREF GPS Sites 0730 Šatorina and 0732 Sveti Nikola estimated within SLOCRO-1994GPS Campaign during the last years were damaged or destroyed, therefore we propose toreplace them with new sites 0730 Kremen and 0732 Vis Hum.

21

The EUREF GPS Sites in the Republic of Croatia with associated coordinates in ETRS-89system is presented in the following table:

EUREF No. SITE NAME X Y Z

0725 DONJI MIHOLOLJAC 4235413.420 1389394.706 4546864.155

0726 NOVOSELSKO BRDO 4273227.943 1314661.906 4533896.905

0727 BRUSNIK 4307966.079 1200393.194 4532778.716

0728 GRADIŠTE 4267436.938 1445417.698 4499533.451

0729 PULA 4396624.036 1083670.705 4476822.858

0730 KREMEN 4386479.599 1248397.099 4446190.519

0731 ŽIRJE 4450950.365 1246404.433 4380514.136

0732 VIS HUM 4486667.279 1296165.147 4330366.220

0733 SVETI IVAN 4466232.614 1404551.057 4317584.872

0734 ILIN VRH 4469744.080 1485678.377 4287027.880

The location of the proposed EUREF GPS Sites in the Republic of Croatia is presented inFigure 2.

8. Comparison with solutions of other GPS Campaigns

The results of EUREF GPS sites computed in the combined solution were compared with theresults of EUVN 1997 GPS Campaign and EUREF-FYROM 1996 GPS Campaign:

GPS Campaign GPS Site ETRS-89 GPS Campaign - CombinedSolution

X dX NorthY dY EastZ dZ Up

(m) (m) (m)

EUVN-1997 BRUSNIK 0727 4307966.082 0.003 0.0041200393.195 0.001 0.0004532778.725 0.009 0.009

EUVN-1997 GRADISTE 0728 4267436.949 0.011 0.0031445417.704 0.006 0.0024499533.467 0.016 0.020

EUVN-1997 MALIJA 0724 4351694.762 -0.003 0.0051056274.718 -0.002 -0.0014526994.584 0.003 0.000

EUREF FYROM-1996 ILIN VRH 4469744.084 0.004 -0.0031485678.378 0.002 0.0004287027.880 0.000 0.003

22

EUREF GPS Sites in Slovenia

LEGEND:

Replaced EUREF GPS Sites in Croatia

EUREF GPS Sites in Croatia

23

9. References

Altiner, Y., Èoliæ, K., Gojèeta B., Lipej, B., Marjanoviæ, M., Rašiæ, Lj., Seeger, H: Results ofthe EUREF 1994 Croatia and Slovenia GPS Campaign, Report on the Symposium of the IAGSubcommision for the European Reference Frame – EUREF, Helsinki, May, 3-6, 1995.

Altiner, Y., Franke, P., Habrich, H., Miškoviæ, D., Seeger, H., Seliškar, A., Tavèar, D.:Results of the Slovenia-95 GPS Campaign, Report on the Symposium of the IAGSubcommision for the European Reference Frame – EUREF, Sofia, June, 4-7, 1997.

Altiner, Y., Becker, M., Dimitar, D., Georgiev, V., Postolovski, V., Seeger, H., Todosov, A.:Results of the EUREF-FYROM-1996 Campaign, Report on the Symposium of the IAGSubcommision for the European Reference Frame – EUREF, Bad-Neuenahr, June, 9-12,1998.

Altiner, Y., Èoliæ, K., Gojèeta, B., Habrich, H., Lipej, B., Neumaier, P., Marjanoviæ, M.,Mediæ, Z., Miškoviæ, D., Pribièeviæ, B., Rašiæ, Lj., Seeger, H., Seliškar, A., Tavèar, D.:Results of a re-computation of the EUREF GPS Campaigns in Croatia and Slovenia, Reporton the Symposium of the IAG Subcommision for the European Reference Frame – EUREF,Bad-Neuenahr, June, 9-12, 1998.

Boucher, C., Altamimi, Z,: Specifications for the reference frame fixing in the analysis of aEUREF GPS Campaign, Meeting of the EUREF Technical Working Group in Bad Neuenahr-Arhweilr, September 29-30, 1993.

Boucher, C., Altamimi, Z.: Specifications for the reference frame fixing in the analysis of aEUREF GPS Campaign, Version 8.01.1998., ftp://lareg.ensg.ign.fr.

Kouba, J.: IGSMail – 1838, ITRF96 IGS Product Change, March, 20, 1998.

Kouba, J.: IGSMail – 2105, ITRF94/96 IGS Change-Update, December, 18, 1998.

Kouba, J.: ITRF TRANSFORMATIONS – IGS Orbits and IGS ERP transformations -TRNFSP3N program explanations.

Marjanoviæ, M., Rašiæ, Lj.: Results of the CROREF-96 GPS Campaign – Internal Report,Institut für Angewandte Geodäsie Frankfurt/Main, March, 1997.

Rašiæ, Lj., Marjanoviæ, M.: Processing results of the CRODYN-94 and CRODYN-96Geodynamic GPS Campaigns – Internal Report, Institut für Angewandte GeodäsieFrankfurt/Main, March, 1997.

Rothacher, M., Mervart, L.: Bernese GPS Software Version 4.0, Bern, 1996.

computation of the combined solution of … of the combined solution of euref gps campaigns...

Documents